I received a lot of emails from our readers after the last coolers roundup. There were mainly two problems our readers wanted to make me aware of. First, there were readers that complained about the fact that there are too many coolers in the roundup and it got boring to read all the pages. A first suggestion was to reduce the comments for every cooler. I do not want to do this so I will come more often with roundups but the number of coolers reviewed in every roundup will be between ten and fifteen. The second most asked question was about the temperature recorded by the motherboard sensor. Many users complained about their motherboards which heat up the CPU to over 60C, even with very good coolers. I tried to explain to them that this is not the motherboard's fault, but the motherboard temperature recording procedure. Once again I have to mention that our results do not differ from the standard temperature measurement procedure described by AMD in their sheets with more than +/- 3C.

From the technical point of view we will test the coolers in the same conditions like in the previous article, so you can compare performance between the two articles. You can read the previous cooler roundup if you want to find out more about the testing procedure, but for safety I included the procedure below. With the Athlon XP appearance on the market the overclocking conditions changed a little bit. Our test CPU generates enough heat to render representative results for medium to upper segment of the market, but there is a small segment uncovered by our testing procedure. Based on test results we will make recommendations for Ahlon XP overclocking.

All the measurements are made with MSI K7T LE and PC Alert III software from MSI under Windows 2000 SP2. The system was stressed using Passmark BurnIn Test. Different motherboards display different results because manufacturers use a mathematical method to approximate the sensor temperature. The method may not be the same, the sensor may not be of the same model and finally the calibration may differ. Certain motherboards are known to provide optimistic results while others are very pessimistic.
Tests were run three times in different days. The results are an average of the day results.
The temperature was recorded using software until it became constant for more than 20 minutes. We measured the temperature with a 100% load applied to the CPU.
Ambient temperature was measured in all cases. After several tests we discovered that the influence of the ambient temperature was almost linear to the CPU temperature, so we averaged it too.
All the tests were made in an open case environment, with no forced air flow around the heatsink.
The noise level was measured inside a sound isolated case using a Super Mini Sound Meter 840014 at a distance of 30cm.
All coolers were installed conforming with our thermal compound installation using Artic Silver. Although several coolers were provided with other interface material we wiped it and tested them with the same thermal interface like the others.

Test system

Before going to actual tests I have to tell you that you should not compare our test results with the temperature showed by your motherboard monitor. We invested a lot of time in making these results as accurate as possible, but the main objective of this round up it's the comparison. The difference between our measurement method and the one displayed by an Omega sensor installed on a Taisol using the AMD method was at most 2.7degrees Celsius, so I think that the results are in an acceptable accuracy interval.

This roundup is targeted mainly to AMD CPUs, the reason why we tested the cooling power with a 1.2Ghz Thunderbird overclocked to 1.33Ghz 1.85V core. This CPU is loaded with more than 75W, so most coolers were stressed by these conditions.
Take a look below to our test bed:

As you can see we didn't use an out of ordinary system. Passmark BurnIn Test was considered able to stress the system with no other help. In the preliminary test sessions we ran several tests and we discovered that BurnIn Test 2.2 is really a very powerful test for measuring system stability. The ambient temperature was measured by an Omega sensor placed at about 30cm distance away from the cooler in order not to be influenced by the cooler airflow.

The noise was measured at 30cm also. You will find that the fan specs talk about a much lower noise than the results of our tests. There are multiple reasons for this. Most manufacturers measure the noise 1m away from the cooler, with no heatsink. When a heatsink is used the noise level is bigger. In the specifications table you can find the noise level rated by the manufacturer of the fan and in the test results our results.